Electrical sensors are used to detect and monitor one or more characteristics of an electrical signal in a conductor. As such, electrical sensors can be used in systems to monitor current levels, voltage levels, power levels, or other aspects of an electrical system. Monitoring one or more electrical signals in an electrical system provides information on the operating conditions of the system, a subsystem, or one or more components in the system. For example, an electrical sensor may be used in control systems in manufacturing and industrial applications. In such applications, an electrical sensor may be used to monitor equipment status, to detect process variations, and to ensure safety of personnel. In addition, an electrical sensor may be used to control pumps, compressors, heaters, conveyors, and other electrically powered devices.
Some electrical sensors are equipped with an alarm that is activated upon the detection of certain operation conditions. The problem with present electrical sensors is that the electrical sensors have a limited dynamic range. In other words, the present electrical sensors are limited to a narrow range between the minimum and the maximum values that can be measured. As such, present electrical sensors are limited to specific applications or systems that have to be specifically designed to accommodate the limited range of electrical sensors.
The high cost of the systems and its individual components as well as the high power used for operating the systems require that the system be shut down to ensure the safety of the equipment and the technician when adjustments are made. In addition, the use of an electrical sensor at the upper and lower ends of a selected operating range creates reliability and accuracy problems. For example, operating an electrical sensor too close to its minimum rated value will not accurately measure values. There is a similar problem operating an electrical sensor too close to the upper limit of an operating range. Because of the problem of accurately monitoring currents at or near the extremes of an operating range, the safety of equipment and personnel may be jeopardized. Further, the limited operating range of an electrical sensor restricts the use to specific systems or applications. In addition, once the electrical sensors have been manually adjusted, the present electrical sensors must be recalibrated. The recalibration requires shutting a system down to adjust manually the electrical sensor, and turning the system back on to verify that the sensor had been adjusted properly. This is repeated until the electrical sensor is properly configured. Alternatively, the electrical sensor can be calibrated off site but the system still must be shut down to reinstall the electrical sensor and must again be verified it is configured properly, which includes turning the system back on and if necessary shutting it down again to reconfigure the electrical sensor. Such a process of adjusting and recalibrating present electrical sensors creates extended down time for a system and adds to the cost of running the system.